A sugar plant can include a cane preparation unit or section, where sugarcane from stock/trucks are transferred to a series of cane carriers which carry the cane to a first mill chute for cane processing. The cane preparation unit is used to increase the cane density by cutting it into smaller pieces referred as cane chips and tearing the cane chips into shreds with no extraction of juice.
The cane carriers include a chopper having knives to cut the cane into smaller pieces, and a shredder to tear the cane chips into shreds. The output from the shredder is sent to the first mill chute and then onto the conveyers to the subsequent mills. The function of the cane preparation unit is to implement a uniform feed of cane to the first crushing mill in the presence of severe loading disturbances which are otherwise present in an absence of the cane preparation unit.
However, the current operation of the cane preparation unit overlooks an energy minimization aspect. In existing cane preparation units, the operators adjust set points for the speeds of the carrier motors based on their experience and the level of the cane in the carriers. It may be noted here that the speed of the last carrier is decided by the level of cane in the carrier, level of cane in the first mill chute, and the first mill chute load. The speeds of the rest of the carriers are decided based on the level of cane in the carrier, speed of the next carrier and knives/shredder overloads (if any). With these different variables, it can be difficult for the operators to optimize for all variables. Therefore the operators mostly focus on reducing the stoppages due to imbalance between the amount of cane crushed in the first mill and that is being conveyed through the carriers to the first mill chute. Minimization of energy consumption is not accounted for in this process.
Therefore, to optimize the operation of the cane preparation unit and reduce the operating costs of the sugar plants, it would be desirable to minimize energy consumption in the cane preparation unit.